1. Field of the Invention
The invention is a clock spring interconnector for enclosing an electrical connector, the clock spring interconnector electrically connecting a rotatable electric device with a stationary electric device.
An increasing number of automobiles have air bag crash systems. An air bag is typically located on the steering wheel facing the driver. The air bag must be in continuous electrical connection with sensors in the car body. The sensors provide an electrical signal to the air bag crash assembly which instantly inflates the air bag in the event of a crash.
Accordingly, there is a need for an electrical connection between the rotatable portion of the air bag assembly which is mounted on the steering wheel, and the remaining portion of the assembly which is in a stationary position in the car body. Electrical connections between rotatable and stationary parts are well known. Typically, an electrical brush rests upon a conductive ring, with one of the parts being rotatable to provide such rotatable electrical connection. However, there is a risk, particularly during the impact of an accident, of a transient failure of electrical connection with a brush and ring system, which would result in failure of the entire air bag system crash assembly.
Accordingly, a clock spring interconnector has been previously developed, comprising an outer housing and a rotor member, the housing and rotor member rotatably associated with one another at a plurality of bearing surfaces. A "clock spring" is located inside the interconnector, the clock spring has two ends conductively attached to conductor wires which pass out of the interconnector to unite the air bag to the sensing device. The interconnector is mounted on the steering column, and the steering wheel may be rotated in either direction while a continuous, positive electrical connection is provided between air bag and sensors via the clock spring interconnector.
While prior art clock spring interconnectors are effective to provide the necessary continuous electrical connection between an air bag or other device on a rotating column and a stationary portion of a circuit, the prior art systems were sometimes wound completely tight before the device was installed making the installed device useless. This problem was partially solved by providing a clock spring assembly with a device that kept the clock spring interconnector from rotating prior to installation. The locking device was destroyed when the clock spring was installed on a rotatable columns. However, the interconnector then became susceptible to over winding and failure if the interconnector was subsequently removed from the column.
2. Prior Art
U.S. Pat. No. 4,722,690 describes a clock spring interconnector which includes a projection locking the rotating portion of the clock spring assembly in a stationary position prior to installation of the assembly onto a steering wheel column for example. Once the projection was removed, the interconnector is able to rotate. However, the projection could not be replaced on the interconnector meaning that the interconnector was free to rotate if it were ever removed from the column.